create table visavmtsbatch (
  b_id number(16) not null,
  b_created_date date not null,
  b_created_by varchar2(100) not null
);


alter table casemast
add c_visa_vmts_batch number(16);


CREATE SEQUENCE SEQ_VISAVMTSBATCH INCREMENT BY 1 START WITH 1;

CREATE OR REPLACE TRIGGER TRIGGER_VISAVMTSBATCH_INS 
BEFORE INSERT ON VISAVMTSBATCH FOR EACH ROW  
DECLARE
  tempId VISAVMTSBATCH.B_ID%TYPE;
BEGIN
  select SEQ_VISAVMTSBATCH.nextval into tempId from dual;  
  :NEW.B_ID := tempId;
END;